Gamecube ISO tool is basically what the name suggests. You can use it to convert between various Gamecube formats for backup purposes or playing on most USB loaders via Dios Mios Lite.
The main purpose of GCIT is as a testbed for gamecube functionality in Wii Backup Manager, but I've tried my best to also make it a usable standalone application.

Features

-Read and write Full size (scrubbed) or trimmed ISO/GCM, GCReEx and DiscEx formats with direct conversion.
-Extract games from GCOS multiboot ISOs to any of the supported formats.
-Command line options for batch processing etc.
-Save the original file layout to trimmed ISOs, allowing full size ISOs to be rebuilt at a later date with the same file layout as the original.

Change log (1.0.1 Build 5):
Fixed: I forgot to remove special characters like ":" from the default filename in the dialog when saving ISO.
Fixed: When uploading the log to the Ctrl-V website, the document title should've been "GCIT log" instead of "Ctrl-V log"